Tunze skimmer principles

[ghomola]

Roger,

I'm new to forums, so bear with me if I make mistakes.

I have had a 58 gallon oceanic with fish only with live rock for around 2 years. I am planning on a reef tank and am looking at skimmers.

I like the idea of Tunze's skimmers not harming plankton, but I am not totally clear how this works. From the description on the Tunze's website, I imagine the following:
-1. Air bubbles that are traveling through a membrane-type contact pipe attract the proteins and cellulose.
-2. The water in the pipe become poor in protein particles and causes a contact gradient between the inside and outside of the contact pipe.
-3. The gradient makes the proteins diffuse from the main water outside of the contact pipe through the membrane/contact pipe to the inside.
-4. The main flow is caused by a seperate sump pump.
-5. The water in the foam inside the contact pipe either goes into the collection cup or get recirculated back to the pump.
-6. Any water that goes out with the foam get replaced by water from the tank.
-7. Plankton is not harmed because:
-----a) the main flow does not get pumped and the foam water is recirculated within skimmer, and
-----b) the pump does not harm the plankton anyways.
Please correct me if I'm misunderstanding how this works.

It says on the Tunze website that "The [Tunze Turbelle] circulation pumps produce no detrimental water jet shearing forces." In another post on this forum, you said this is accomplished by a large pump outlet diameter. I'm assuming this means the impeller does not damage plankton either. Are these same type of pumps used on the skimmers?

For my 58 gallon tank, I am considering a 220/3 or a 3115/2 skimmer. There is a sleeve and hose 240.80 to remove foaming water into an exterior container. But as far as I can tell, the sleeve and hose is only for skimmers 240/3, 245/3, 3140/2, and 3160/2. Is there a way to do this with the 220/3 or 3115/2?

I am thinking of removing wet foam from a skimmer continuously into a waste collection container. This removing of wet foam would be my water change system. I would use an automatic top off system with some salt in the water to replace both evaporation and the wet foam. It would take some time to figure out the correct amount of salt in the top off water.

Any comments on this method of "automatic water changes"? You have mentioned that Tunze skimmers are not good at particulate removal. Would removing wet foam with a Tunze skimmer remove the particulate matter and eliminate the need for a mechanical filter?

Thanks for your help,

Gary

 

[rvitko]

The Tunze skimmers operate on a plankton safe principal by using diffusion to remove proteins and cellulose. You have the essential idea but no other pump is required. The skimmer has a pump inside and this recirculates the water in the skimmer. By diffusion dissolved materials enter the skimmer due to an osmotic gradient- you will remember the principal that in a solution the solute is evenly distributed in the solvent, since you removed solute from inside the skimmer the solutes remaining outside the skimmer diffuse in. The diffusion occurs through a few small openings on the front of the skimmer. Really nothing complicated about the skimmers they have a Turbelle pump, a venturi, a collection cup and a plastic body. Nice features are they are almost dead silent and the skimmer cups shut down when full so they can't overfoam.

The Turbelle pumps are plankton safe by minimizing shearing force. I don't agree that impellers do the damage. These tests from my reading were done with adult brine shrimp and generally invalid in real world contexts. The impellers do utilize a unidirectional shape that sweeps water out and so probably is better than most but I don't think that it is impellers themselves that destroy plankton.


I don't know a way to really do the automatic water changes you describe outside of the Dialyseas units or I think the Reeffiller dual unit can do that. The Tunze method was developed as a complete system to meet new restrictions that were being considered in Germany on disposing of saltwater. The components when complete and properly applied eliminate the need for most routine water changes. A full set up would include a skimmer, a mechanical filter set with cartridges being rinsed or replaced weekly and bio reactor to digest nitrate and phosphate. It would also include an osmolator for auto top off of evaporation and a calcium reactor to maintain KH and calcium without the inherent problems of calcium chloride and buffers.

The foaming water removal tube- ahem, sucks. Just use the cup. The skimmer cups work really well and hold quite a bit. The auto shut down feature is really neat and they are esy to remove and clean.

 

[ghomola]

From reading some other posts on this forum, it seems you set the height and then adjust the air flow in order to get your preferred skimmate. If I wanted to remove lots of wet foam, could I do so?

Thanks,

Gary

 

[rvitko]

In general the skimmers remove a tea colored skimmate- a bit lighter than most skimmers. Ideally the water level is constant and their is little room for adjustment. For the most part the venturi is the adjustment. It is generally nor possible to get a consistently watery skimmate as the diffusion gradient principle combined with the wide diameter of the foam column prevent building up a stable foam column if their is really nothing to remove. This can be countered by using a surfactant like a colloid- hydrocoll by Hw comes to mind as I have used it as a stress coat and it definitely causes the skimmer to overreact. I think if you are set on doing this you might consider Euro Reef as your best option.

 

[ghomola]

I'll have to think about this idea. Thanks for your forthright and honest opinions.

Gary